1. Field of the Invention
The present invention relates to a bandwidth control apparatus and a communication control semiconductor, and particularly to a bandwidth control apparatus and a communication control semiconductor in which in a communication field such as an IP network, a usable bandwidth is calculated based on a previously set minimum bandwidth and maximum bandwidth, and information of a communication amount or session connection time, and bandwidth control can be performed.
2. Description of the Related Art
Since the access control of Ethernet technique (Ethernet is a registered trademark) used in an Internet network or in-company LAN is controlled by the Carrier Sense Multiple Access/Collision Detection (CSMA/CD) system, there is a characteristic that the bandwidth is liable to be occupied by a user who transmits and receives many packets. That is, when a user (hereinafter referred to as a heavy user) who exerts an excessive network load exists on the same line, there is a case where the communication bandwidth of a user who infrequently conducts the communication or whose communication amount in a specific time is low (hereinafter referred to as a light user) is not sufficiently ensured. Thus, an Internet Services Provider (ISP) to provide continuous access to the Internet uses a packet relay apparatus having a bandwidth control function to prevent unfairness in usable bandwidth between users.
As the technique to provide the bandwidth control function as stated above, for example, JP-A-2003-198611 discloses a bandwidth control method using a minimum bandwidth and a maximum bandwidth for each user, in which a transmission right is given to a buffer in a state where a leaky packet level exceeds the minimum bandwidth.
JP-A-2003-318967 discloses a bandwidth control technique in which between an input side node to transmit a packet and an output side node to receive a packet, a transmission permissible rate of a data packet to be transmitted to the output side is determined based on information included in a control packet in which control packet transmission time and a data accumulation amount are recorded.
As one of reasons why the line bandwidth of each ISP is stressed, there is a Peer to Peer (P2P) application. The related art server-client type communication includes a server which concentrically manages information resources and a client which uses the information resources managed by the server, and there is a case where load is concentrated on the server. On the other hand, in the P2P-type communication, each terminal functions as both the server and the client. In the P2P network, when an access is made to information resources, the information resources are transmitted through an adjacent client, and the information resources are stored also in the client of the relay node, so that the information resources are spread. Since the client can function as the server by using the spread information, there is a feature that local concentration of loads can be prevented. Although the P2P is a excellent communication technique, there is a case where for example, copyright infringement material circulates on the P2P network, and an increase in traffic of the whole network is consequently caused. From the background as stated above, the movement of regulating the P2P application communication as the factor of the traffic increase occurs gradually in the ISP.
As the technique to provide such a bandwidth control function, for example, JP-A-2005-202589 discloses a technique in which a dummy node such as a honey pot is installed, a traffic corresponding to the P2P application is guided, analysis is performed up to the application layer of the traffic, and the bandwidth control is performed.
Besides, JP-A-2008-48131 discloses a bandwidth control in which feature points of a P2P application are statistically grasped, and particularly, attention is paid to the feature points of the SYN/ACK process of the P2P application, and it is determined by a statistical method whether or not the traffic is the P2P application.